>>32943431B and D.
The most likely pokemon to be preserved are those with hard parts and "true" steel type pokemon did not exist yet.
If you think of the evolutionary arms race, you start with Normal, Water, and Bug. Water because life started in the ocean, Bug because many primitive life forms were vaguely arthropedic, and Normal because it's, well, normal.
Pokemon with tough armor better resist the unfocused battering of primitive, normal attacks, and can be used to crush the bug types most likely used as food.
Water attacks are likely underdeveloped because either A: A large chunk of prey species resist water, and B, early Water pokemon had a hard time moving to land.
Thus, with virtually no weaknesses, it would only make sense to adopt rock typing, even if only through thick hides or shells as opposed to "true" rock-ness. Later on, many types developed to combat the rock type, which is why Rock has so many weaknesses. It also handily explains Bastiodon's proto-Steel typing, as it had to defend against rock-type attackers
Support: Relicanth is Rock type despite not being reanimated, and was alive at the time.
I doubt the reanimation changed them, because you aren't "ressurecting" the pokemon, you are cloning it. If you were ressurecting it, you would only be getting the skull of a Cranidos or the shell of an omanyte, when there is clearly a whole pokemon. That's the entire point of the Old Amber reference. If something looses a leg, gets covered in parasites, or gets coated in rock, this is not reflected in its DNA.
Plus, why wouldn't Aerodactyl be Flying/Grass then? It was coated in tree, not rock.
